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A number of factors affect the performance of a racing or training surface according to the 34-page “Racing Surfaces White Paper” published in June this year.This international publication is a valuable collection of scientific papers co-authored by an esteemed panel including: Dr. Mick Peterson, (University of Maine), Dr. Jeffrey Thomason (University of Guelph), Dr. Lars Roepstorrf (Swedish University of Agricultural Science),Dr. C. Wayne McIlwraith, (Colorado State University), and Christie Mahaffey, MPhil (University of Maine).Though there is still much research to be done since the forming of the racing surfaces committee at the inaugural Welfare and Safety of the Racehorse Summit in 2006, this publication will benefit trainers, track superintendants and any person in charge of riding surfaces.Details of proper maintenance of surfaces and training guidelines can be found, based on the knowledge gained from the researcher’s findings thus far.The download is available at grayson-jockeyclub.org/resources/White_Paper_final.pdf

Queensland is experiencing the Hendra virus. The following is basic information about the virus, history, signs and symptoms, diagnosis, vectors and more.

Key facts

Hendra virus can cause fatal respiratory and neurological diseases.

Hendra virus can be transmitted to people from horses.

Hendra virus can cause severe disease and death in horses.

There is no treatment or vaccine available for either people or horses.

Fruit bats of the Pteropodidae family are the natural hosts of Hendra virus.

Hendra virus (HeV) is a rare, emerging zoonotic virus (a virus transmitted to humans from animals), that can cause respiratory and neurological disease and death in people. It can also cause severe disease and death in horses, resulting in considerable economic losses for horse breeders.

Initially named Equine Morbilivirus, Hendra virus is a member of the genus Henipavirus, a new class of virus in the Paramyxoviridae family. It is closely related to Nipah virus.

Although Hendra virus has caused only a few outbreaks, its potential for further spread and ability to cause disease and death in people have made it a public health concern. The concern has heightened in the most recent outbreaks, as the horses’ symptoms have shifted to become largely neurological instead of respiratory. This suggests the possibility of genetic diversity in the strain, and potentially a more infective virus.

Outbreaks

Hendra virus was first recognized in 1994 during an outbreak of acute respiratory disease among 21 horses in Australia. Two people were infected, and one died. Since then, there have been another ten outbreaks, all in Australia, and three involving human cases.

Transmission

Hendra virus is transmitted to people through close contact with infected horses or their body fluids.

To date, no human-to-human transmission of Hendra virus has been documented.

The incubation period (interval from infection to onset of symptoms) ranges from five to 14 days. To date, there have been six confirmed human cases including three deaths.

One of the people who died developed pneumonitis, respiratory failure, renal failure, and arterial thrombosis. The patient died of cardiac arrest.

Another person demonstrated an unusual, progressive fatal neurological illness. He initially had a mild type of inflammation of the brain (meningoencephalitis) with a sore throat, headache, drowsiness, vomiting and neck stiffness. After treatment with antibiotics, he made a full recovery, but 13 months later he developed signs of encephalitis that progressed to coma and death.

The three infected people who made a full recovery have had no residual problems or relapse.

Diagnosis

Hendra virus infection can be diagnosed by a number of different laboratory tests:

serum neutralization;

enzyme-linked immunosorbent assay (ELISA);

polymerase chain reaction (PCR) assay;

immunofluorescence assay; and

virus isolation by cell culture.

Treatment

There are currently no drugs or vaccines available to treat Hendra virus infection. Intensive supportive care with treatment of symptoms is the main approach to managing the infection in people.

Natural host of Hendra virus

Fruit bats of the family Pteropodidae – particularly the species belonging to the Pteropus category – are the natural hosts for Hendra virus. There is no apparent disease in fruit bats.

It is assumed that the geographic distribution of Henipaviruses overlap with that of Pteropus genus. This hypothesis was reinforced with the evidence of Henipavirus infection in Pteropus bats from Australia, Bangladesh, Cambodia, China, India, Indonesia, Madagascar, Malaysia, Papua New Guinea, Thailand and Timor-Leste.

Recently, African fruit bats of the genus Eidolon, family Pteropodidae, were found positive for antibodies against Nipah and Hendra viruses indicating that these viruses might be present within the geographic distribution of Pteropodidae bats in Africa.

Hendra virus in horses

Horses are the only species of domestic animal that can be naturally infected with Hendra virus. Infections in horses range from asymptomatic infection to fatal respiratory and neurological syndromes. For fatal cases, the course of illness takes an average of two days.

Symptoms of Hendra virus infection in horses are not dramatically different from other respiratory and neurological illnesses of horses. Hendra should be suspected if there is also the proximity of bats, or the presence of human cases of acute respiratory distress syndrome or encephalitis. Generally Hendra virus outbreaks in horses occur one to two weeks before illness in humans; detected outbreaks in horses could trigger prevention measures to deter associated outbreaks in humans.

The incubation period (interval from infection to onset of symptoms) in horses varies between five and 16 days. The case fatality rate in horses is about 75%.

Spill-over of Hendra virus from fruit bats to horses is rare. The transmission route is likely through contamination of pasture or feed by infected birthing fluids or fetal tissues from bats.

Prevention

Preventing transmission in horses

There is no vaccine against Hendra virus. Routine cleaning and disinfection of horse stables is expected to be effective in preventing infection.

If an outbreak is suspected, the horse premises should be quarantined immediately. Culling of infected animals – with close supervision of the burial or incineration of carcasses – may be necessary to reduce the risk of transmission to people. Restricting or banning the movement of horses from infected stables to other areas can reduce the spread of the disease. As Hendra virus outbreaks in horses have preceded human cases, establishing an animal health surveillance system to detect new cases is essential in providing early warning for veterinary and human public health authorities.

Reducing the risk of infection in people

In the absence of a vaccine, the only way to reduce infection in people is by raising awareness of the risk factors and educating people about the measures they can take to reduce exposure to the virus.

Public health educational messages should focus on the following.

Reducing the risk of horse-to-human transmission. Protective equipment such as gloves, gowns, masks and protective eyewear should be worn while handling sick animals or their tissues, and during post-mortems.

Reducing the risk of bat-to-horse transmission. Horse feed and water troughs should be relocated to areas away from where bats feed or roost.

Controlling infection in health-care settings

Health-care workers caring for patients with suspected or confirmed Hendra virus infection, or handling specimens from them, should implement standard infection control precautions.

Samples taken from people or horses with suspected Hendra virus infection should be handled by trained staff working in suitably equipped laboratories.

Nutrition and particularly changes in feeding are often associated with colic. Several survey-based studies have been performed to better determine what roles diet and dietary changes play in the incidence of colic. A case-matched survey study performed by Noah Cohen, D.V.M., Ph.D., and coworkers at Texas A&M University identified the following risk factors that increased the chances of a horse being treated for a colic emergency.

1. Changing the horse's diet within the previous two weeks increased the chances of colic 6.6 times.

2. Recent change in type of hay within the previous two weeks was the only specific dietary change that was significantly associated with an increased risk for colic (29.5 times).

3. History of previous abdominal surgery for colic increased the risk of colic by 5.8 times. Horses that have had previous abdominal surgery for colic can sometimes develop adhesions (scar tissue) that prevents normal movement of their intestines.

4. Chances of colic were increased 3.1 times if there was a substantial change in weather conditions in the previous three days. The exact weather change was not further described.

5. A change in housing within the two weeks before being treated for colic almost doubled (1.9 times) the chance of colic.

6. Arabian horses were 1.7 times more likely to be treated for colic than other breeds. Arabians were also more likely to be examined for colic in other studies.

7. Deworming within 7 days prior to colic increased the chances of colic by 1.8 times. However, horses that were regularly dewormed had a decreased risk of colic.

8. Horses that were kept in stalls greater than 50% of the time were 1.2 times more likely to colic than horses that were turned out greater than 50% of the time. Horses that were kept on pasture were significantly less likely to colic.

9. A change in activity during the two weeks before being examined for colic doubled (2.2 times) the chance of colic.

Other studies have also associated a recent change in diet with an increased risk of colic. This emphasizes the importance of feeding a consistent source of hay and making gradual changes when changing feedstuffs. Mature hay will have a higher fiber content that will lower its digestibility and possibly cause impaction colic. Hay quality and maturity can fluctuate widely.

This study also showed that a recent change in diet, particularly hay, was associated with colic. Any dietary change should be made slowly over 7-10 days, and if hay from a different source must be fed, the amount should be gradually increased as the previous hay is depleted.

Photo courtesty of The Western College of Veterinary Medicine (www.wcvm.com)

By Katharina Lohmann, MedVet, PhD, DACVIM

Tying-up syndrome, or rhabdomyolysis, is a myopathy (disorder affecting the body’s muscle system) that causes muscle-cell destruction and decreases an affected horse’s performance. Common systems include painful muscle cramping and hardening as well as severe increases in muscle enzymes that can be detected through laboratory testing.

Exertional rhabdoyolyses are disorders that typically occur in horses performing exercise beyond their conditioning status — or horses performing strenuous exercise after a period of rest and inactivity. Exertional rhabdomyolysis may be sporadic or can chronically recur in some affected horses.

Sporadic exertional rhabdomylosisoccurs in horses performing exercise beyond their conditioning status and in horses performing strenuous exercise after a period of rest and inactivity.

• Clinical signs: The signs, which can appear very quickly, include a reluctance to move and/or a stiff gait, firm and painful muscles, weakness and fatigue, and signs of anxiety such as sweating, rapid heartbeat and rapid breathing. Some affected horses may also pass dark urine, and in severe cases, affected horses may go down.

• Risk factors: Inadequate conditioning, high carbohydrate intake, deficiency in vitamin E and/or selenium, hypothyroidism, and bacterial or viral infections are some of the risk factors that veterinary researchers have considered. However, the evidence supporting these factors is still unclear. Since female horses seem to be predisposed, hormones may be a factor. Differential diagnoses of lameness, colic, pneumonia, back pain or neurological diseases can be ruled out by a complete physical examination and with lab tests of blood and urine.

• Treatment:Treatment includes rest, intravenous and/or oral fluid therapy, non-steroidal anti-inflammatory drugs(NSAIDS) for pain control and, if necessary, sedatives to control anxiety. If deficiencies in vitamin E and selenium are identified, supplements should be provided. In the disease’s acute stages, horses shouldn’t be forced to move, and their return to exercise should be based on improved lab results as well as their willingness to move.

Recumbent horses should have soft bedding to prevent injury, and their caregivers should encourage them to stand and turn every few hours to avoid bedsores. If a horse can’t stand, the animal should be turned every few hours. In some cases, it may be necessary to use a sling to help an affected horse stay upright. However, horses that are in pain should not be forced to stand for extended periods of time.

• Prognosis:The prognosis for recovery is generally favourable as long as the animal is treated early enough and doesn’t develop complications such as kidney failure. The recovery time depends on the severity of the disease; an adequate rest period and gradual return to exercise are required. Proper conditioning and regular exercise — including pasture turn-out — are also recommended. Chronic recurrent rhabdomyolysis: This disease group causes recurring episodes of rhabdomyolysis. The severity and the intervals between episodes can vary greatly, and genetics may be an underlying factor.

To maintain their athletic capability, affected horses require careful lifelong management as well as changes in their diet and exercise regimen. Horses that are diagnosed with this condition may never be able to perform as racehorses or participate in other high-level performance events. On the other hand, they may do well in other less challenging occupations.

Polysaccharide storage myopathy (PSSM)is a common cause of chronic recurrent rhabdomyolysis in quarter horses, paints and appaloosas as well as in warmblood breeds and draft horses. PSSM is caused by a genetic defect that’s particularly common in PSSM-affected quarter horses and draft-related breeds. As a result, veterinarians recommend genetic testing for some breeds.

• Clinical signs:Clinical indications of PSSM include repeated episodes of “tying-up” with less than strenuous exercise, muscle stiffness during and after work, exercise intolerance, and, possibly, changes in behaviour.

• Diagnosis: The first step in diagnosing PSSM is ruling out other causes such as lameness through careful examination and laboratory tests. The next step is often exercise testing which may be followed up with further diagnostics like muscle biopsy and genetic testing.

• Treatment: Veterinarians recommend mild exercise as soon as possible for PSSM-affected horses. Other recommendations include making dietary changes, maintaining an ideal body weight and following a specific exercise regimen.

Dietary changes involve reducing carbohydrates and increasing fat as an energy source. While commercial diets are available, an alternative is to gradually add rice bran or vegetable oils to the horse’s feed. High-performing horses may require additional calories in their diet.

Regular exercise is important; pasture turnout is ideal and stall rest should be limited as much as possible. Unless there’s adequate preparation and conditioning, horse owners must avoid sudden changes to an affected horse’s exercise regimen — such as a long trail ride. As well, affected horses shouldn’t take long trips in a trailer or be involved in other stressful events.

Owners who follow veterinarians’ recommendations for diet and exercise are more likely to see a reduction in the frequency and severity of PSSM episodes in horses diagnosed with this condition.

Recurrent exertional rhabdomyolysis (RER)is a condition that presents similar symptoms to PSSM and is mainly diagnosed in thoroughbred and standardbred racehorses.

• Risk factors:Episodes of RER may be related to the stress of training and racing. Young horses — particularly fillies and horses with nervous dispositions — may be at a higher risk. Researchers have also identified high-grain rations and certain training strategies as possible risk factors for RER.

• Diagnosis: Exercise testing and a muscle biopsy are the most useful tools for diagnosing RER.

• Treatment: Managing RER is similar to PSSM in terms of diet and exercise. As well, it’s essential to reduce stress in affected horses’ lives. For example, owners should standardize the horses’ daily routines. The animals should be exercised and fed before their barnmates, and low doses of anti-anxiety drugs may be given prior to exercise. Several drugs such as dantrolene (a muscle relaxant) and phenytoin (an anti-convulsant drug) may be helpful in preventing episodes of rhabdomyolysis in affected horses, but these medications should only be used under veterinary direction.

Summary

Rhabdomyolysis remains an important cause of morbidity and mortality in horses. Recent advances in identifying underlying myopathies, some of which are now known to be genetically determined, have helped veterinary researchers gain a better understanding of this group of disorders and to develop more specific treatment and management recommendations.

To optimize management and to make important breeding decisions, it’s important for horse owners and their veterinarians to pursue thorough diagnostic testing of animals with rhabdomyolysis — especially if it’s a recurring problem.

Reprinted with permission of Horse Health Lines, news publication for the Western College of Veterinary Medicine’s Equine Health Research Fund. Visit www.ehrf.usask.ca to sign up for Horse Health Lines’ e-newsletter.

Since widespread flooding is predicted on the Prairies this year, livestock producers and horse owners living near areas where anthrax cases were previously reported may be considering vaccinations as a preventive measure.

But before horse owners make a decision about vaccinating, Dr. Chris Clark of the Western College of Veterinary Medicine (WCVM) recommends that they talk to their veterinarians first.

“Horses are relatively resistant to anthrax, and they’re even more unlikely to get exposed to the bacteria because of the way most owners keep their horses in smaller pastures or paddocks. Consequently the risk is typically very low,” explains Clark, a specialist in large animal medicine who has been involved in previous anthrax investigations in the United Kingdom and in Western Canada.

“Only people who live in high risk areas and manage horses like cattle and other livestock are at a high risk for anthrax.”

Anthrax is a reportable disease in Canada that’s caused by the bacteria Bacillus anthracis whose spores can survive in soil for decades. Cattle, horses, bison or deer can ingest anthrax when they graze in areas where flooding or digging has brought the bacterial spores to the surface.

Once ingested, the spores germinate and grow in an animal’s intestinal tract — releasing potent toxins that cause the animal to die if left untreated. Clinical signs of anthrax include bloody discharge from the animal’s nose, mouth, anus or vagina, abdominal swelling and a carcass that decomposes very quickly. The mortality rate in the early stages of an anthrax outbreak is nearly 100 per cent.

According to veterinarians at the Canadian Food Inspection Agency (CFIA), anthrax is different from other reportable diseases. It’s considered to be an environmental disease since its spores are in the soil and they’re available in a wide, geographic region.

In 2006, an unusually wet spring followed by nearly four weeks of hot weather created ideal conditions for anthrax — especially in north-central and northeastern Saskatchewan. By mid-September 2006, more than 900 animals had died — including five horses and one donkey — from anthrax on 174 positive premises in 51 rural municipalities throughout Saskatchewan and Manitoba. CFIA also reported cases of anthrax on a bison farm near Bonnyville, Alta.

Although anthrax is a non-contagious disease, the bacterial spores can “spread” to other areas through scavengers, migrating birds or flies. Excessive moisture and flooding can also wash anthrax spores from one area to another.

To control the spread of bacterial spores, producers and veterinarians shouldn’t open the carcasses of any animals suspected of dying from anthrax. Once a diagnosis is confirmed, all animals on infected premises are placed under a 21-day quarantine. Carcass disposal is extremely important, and it’s crucial that it’s done very quickly by incineration or by deep burial.

CFIA vaccinates all animals on quarantined farms and recommends revaccination for at least three years on anthrax-positive premises. Producers on neighbouring farms aren’t required to vaccinate their animals, but during the 2006 outbreak, veterinarians advised producers to vaccinate all herds within 10 kilometres of anthrax-positive premises.

More than 550,000 anthrax vaccine doses were distributed across the Prairies during the summer of 2006. The only anthrax vaccine that’s licensed in North America is manufactured by the Colorado Serum Company (www.colorado-serum.com). The vaccine is available for cattle, horses, mules, sheep, goats and pigs, while off-label use can be considered for bison and farmed elk and deer.

The live culture anthrax spore vaccine, which was introduced in the 1950s, is highly effective and considered to be safe with minimal risk to animals and to humans.

However, Clark points out that the anthrax vaccine typically causes significant reaction (such as local swelling) at the injection site — an issue that can be particularly upsetting for horse owners.

As well, the vaccine company and the WCVM now advise owners of miniature horses and young foals to use other alternatives for preventing the disease. This warning comes after at least nine miniature horses in the region died of an apparent adverse reaction to the anthrax vaccine in the summer of 2006. The deaths are under investigation, but until more confirmed information is available, Clark says it’s best to take preventive precautions with smaller horses — a recommendation that’s now included in the vaccine’s packaged information.

“If you’re in a high risk area, it’s best to take the small horses — the miniatures and young foals — off pasture and give them preserved feed and hay. They should also have access to water from a water bowl, just to be on the safe side,” explains Clark.

“What producers must keep in mind is that this particular vaccine has saved countless lives over the past 50 years. It’s a tested product that’s well documented to work in cattle, swine, sheep, goats and horses. Severe adverse reactions to this vaccine are highly unusual.”

Once animals receive the vaccine, it takes from seven to eight days for them to build up enough immunity against the disease. In circumstances where an animal is already exposed to anthrax, Clark says that it’s better to treat with antibiotics such as oxytetracycline or penicillin, then vaccinate the animal later. “What’s important to remember is that you can not give the vaccine and treat with antibiotics at the same time.”

For more information about anthrax, please visit the Farm Animal Council of Saskatchewan’s web site (www.facs.sk.ca) or the Canadian Food Inspection Agency (www.inspection.gc.ca).

Reprinted with permission of Horse Health Lines, news publication for the Western College of Veterinary Medicine’s Equine Health Research Fund. Visit www.ehrf.usask.ca to sign up for the EHRF e-newsletter.

Chestnuts—those patches of rough tissue on the inside surfaces of the front legs just above the knees—are structures that remind us of the horse’s origin as a creature with more than one toe on each foot. Horses also have chestnuts on the insides of the hind legs; these are found just below the hocks. Often explained as toenail remnants from previous eons, chestnuts are actually vestiges of foot pads, the tough-fibered cushions that animals walk on. Think of cat or dog feet, and visualize the hairless toe pads found on the bottoms of the feet. These are foot pads.

Like human fingerprints, the basic outlines of the chestnuts are unique for each horse.

At this point, we need a quick review of general anatomic terms that apply to many animals, although the structure of a horse’s leg is actually quite different from this simplified explanation. “Digital” refers to fingers or toes; “carpal/tarsal” refers to the area of the wrist/ankle in the front and rear limbs, respectively; and “metacarpal/metatarsal” refers to the area of the hand/foot in the front and rear limbs, respectively. Animals like bears that walk on the entire foot with the heel touching the ground have digital, metacarpal/metatarsal, and carpal/tarsal pads on each foot, while animals that walk more on their toes without touching the heel down (cats and dogs) have digital and metacarpal/metatarsal pads, with small or absent carpal/tarsal pads.

In today’s horses, vestigial carpal and tarsal pads are seen as chestnuts, while rudimentary metacarpal and metatarsal pads are seen in the front and hind feet, respectively, as the ergots. These small knobs of tough tissue protrude from each lower leg at the back of the pastern, where they are obscured by the hairs of the fetlock but can easily be felt. The only functional foot pad seen in the modern horse is the frog, a structure found in the rear section of each hoof and extending into the bulbs of the heels. Sweat glands in the frog produce secretions that may have functioned as trail or territorial markers in prehistoric times. Canids (dogs, wolves, foxes) and pigs share this trait.

Like human fingerprints, the basic outlines of the chestnuts are unique for each horse and are recognized by the Federation Equestre Internationale (FEI), the governing body of international equine competition, and other organizations as identifying marks. The FEI horse identification manual states, “The shape of a chestnut should be drawn in outline and related to the vertical.”

Chestnuts grow out slowly and can be peeled or trimmed back if they become excessively long. Chestnuts that are very hard and dry can be softened by applying petroleum jelly or baby oil for several days. There is living tissue at the base of each chestnut, and the area will bleed if too much of the dry layer is pulled off. Don’t try to twist the chestnuts off, as this will pull the surrounding skin and cause pain. Occasionally, horses that are very ill can actually shed their chestnuts.

• providing you with an opportunity to expand your knowledge of the horse industry;

• teach you how to develop your own equine-assisted facility/business;

• and/or compliment your existing social service/counseling business.

Learning how to become a competent, certified EAL facilitator with the help of horses is not only a fun and exciting career choice but is now available and affordable through the Cartier Equine Learning Center.In the past, horse handlers, human behavior specialists and equine facilities interested in offering equine-assisted learning experiences have struggled with curriculum development that can adequately service their clients needs since there has been little to no educational guides available.Individual experimentation has been the most common approach, leaving an up and coming industry wondering where and how to start.

The Learning Center also provides a complete educational curriculum for immediate implementation upon graduation.This interactive educational guide is designed to lead you through to successfully facilitating a wide range of different sized groups, varying in age and abilities.

Horses are extremely sensitive, aware of their surroundings and quick to react.For their mere survival, a wild horse, must constantly be on his guard.Through herd training, they learn the value of trust and respect.Nature provides them with instincts and senses that are very astute.They watch for the slightest movement and look for threatening body posture.Horses have the innate ability to discern the difference between a calm non-threatening approach as opposed to perceived anxious nervous energy.If one can understand how and why horses have this ability to be aware of our every movement — one will come to understand how these unique programs positively effect individuals facing challenges in their lives.This astute sensitivity of the horse acts as a mirror to reflect the difficulties an individual may have.Proper facilitation provides an opportunity to direct the individual how to succeed long term.

How does equine-assisted learning affect individual participants?

Equine-Assisted Learning has proven to be a practical approach to teaching participants alternative skills to draw from when faced with difficult challenges in an effort to overcome negative influences.